# Posts by Chris

Total # Posts: 2,755

psychology
what is the study called where the same people are tested repeatedly at different ages?

Statistics
I need to know how to find the probability that z0 is greater than or equal to 2.40 using my TI-83+. The answer is .008200, but I don't know how to get that using my calculator. The only reason I know the answer is because it is an example from my homework. Please help! On...

Finite Math
A student dance committee is to be formed consisting of 3 boys and 4 girls. If the membership is to be chosen from 7 boys and 6 girls, how many different committees are possible?

Algebra
The grade of a highway up a hill is 50%. How much change in horizontal distance is there if the vertical height of the hill is 175 feet?

Chemistry
how do you find the pH of a titration solution at its halfway point to the equivalence, and how would it affect solutions dealing with strong acids and strong bases, this is an example just to see it quantitatively: 100.0 mL of 0.100 M HF (Ka = 7.2 x 10-4) by 0.100 M NaOH

college physics
i figured out the first part using the fact that the crate will flip over once the CG is no longer above the crate, and drew a triangle of legs 1.44 m(distance from base of crate to CG), and 1.25m(distance from corner of crate to middle). at first i thought the answer would be...

college physics
A cubic crate of side s = 2.5m is top-heavy: its CG is 19cm above its true center. Part A How steep an incline can the crate rest on without tipping over? Part B What would your answer be if the crate were to slide at constant speed down the plane without tipping over? [Hint: ...

Physics
An object is placed 11 cm in front of a convex mirror of focal length 4 cm. Using the lens equation, find where the image will form and state whether it is a real or virtual image.

After receiving a grant for music education, a school decides to build a new band room for its expanded music program. Quadrilateral ABCD represents the floor plan of the new band room. What is the area of the room? AE = 32 ft. BE = 12 ft. CE = 26 ft. DE = 26 ft. There is a ...

Math 8th Grade (Ms. Sue) ?
An artist makes a painting that is 12 feet by 9 feet. He paints a frame around the painting. The frame is 3 inches wide. What is the area of the frame? Please provide formula for figuring out. Answers (a)10.75ftsq(b)10.5ftsq (c)12.96ftsq(d)5.3125ftsq Thanks.

Chemistry
not much of a question but more of an appreciation, thanks for helping i was really confused before today

Chemistry
consider 1.0 L of a solution which is 0.55 M HF and 0.2 M NaF (Ka for HF = 7.2 x 10-4). Calculate the pH after 0.10 mol of HCl has been added to the original solution. Assume no volume change on addition of HCl. Goes along with the last one i posted, i know i have to realize ...

Chemistry
never mind i understand where you were getting at thanks

Chemistry
do i have to account for the NaF, when plugging in the concentration for F^-. The reason im confused is because they are both weak in respect to their acidity and base that wont allow them to dissociate and i don't really know where to go from there

Chemistry
consider 1.0 L of a solution which is 0.55 M HF and 0.2 M NaF (Ka for HF = 7.2 x 10-4), Calculate the pH of this solution

Statistics
I need to know how to find the probability that z0 is greater than or equal to 2.40 using my TI-83+. The answer is .008200, but I don't know how to get that using my calculator. The only reason I know the answer is because it is an example from my homework. Please help!

Math
How can I get 24 out of 2.4, 7.5, 1, and 6 using +, -, *, and/or /

programming
Using Raptor, create a condition loop that will ask the user for input of two numbers. The numbers should be added and the sum displayed. The loop should also ask the user if he or she wishes to enter two more numbers and perform the operation again, the response to the ...

chemistry
Naphthalene, commonly known as moth balls, is composed of 93.7% carbon and 6.3% hydrogen. determine the empirical for naphthalene. molecular formula for Naphthalene. Determine the number of empirical formulas you would need to make a full naphthalene molecule.

chemistry
Vanadium oxide is used as an industrial catalyst. The percent composition of this oxide is 56.0% vanadium and 44.0% oxygen. Determine the empirical formula for vanadium.

calculus
-24/25

programming
Develop psuedocode to control operation of vending machine The ACME Company has approached you with a request to develop the psuedocode that will control the operations of their new series of vending machines. The program will be required to maintain the product inventory and ...

chemisrty
how many liters of oxygen can be produced at stp from the decomp. of .25 liters of 3M H2O2 ACCORDING TO THE REACTION 2H2O-2 H2O+O2

algebra
(3a^4b+4ab^3)+(5ab^3-3a^4b

I don't know the formula to figure this out. Charlie and Peter are driving around a racetrack. Charlie drives at an average speed of 108 miles per hour. Peter drives at an average speed of 99 miles per hour. Peter is given a head start of 12 miles. Charlie and Peter finish...

An archaeologist has set up a dig at a newly discovered site. She and her team start excavating an area that is 36 feet by 24 feet. Because the scientists find many artifacts near the edges of this area, they decide to expand the dig. They add nine feet in all directions to ...

Charlie and Peter are driving around a racetrack. Charlie drives at an average speed of 108 miles per hour. Peter drives at an average speed of 99 miles per hour. Peter is given a head start of 12 miles. Charlie and Peter finish at the same time. How far does Charlie drive? ...

physics
.020m/s^2

math
Ms Sue, can you help please?

math
Charlie and Peter are driving around a racetrack. Charlie drives at an average speed of 108 miles per hour. Peter drives at an average speed of 99 miles per hour. Peter is given a head start of 12 miles. Charlie and Peter finish at the same time. How far does Charlie drive? ...

Math
The area of a circus ring is about 1,385 square feet. What is the circumference of the ring?

Math
Franco is ordering lunch with a drink, sandwich, and a salad. He has a choice of 3 drinks, 2 sandwiches, and 4 salads. How many possible lunches are there? 3*2*4=24 lunches?

Physics
A baseball player throws a baseball up at 24.3 m/s. How long must he wait before he can catch the baseball on its way down?

Math
Explain how you can determine whether a system of two linear equations will be consisten, dependent, or inconsistent?

chemistry
CH3CH2CH=CHCH3 --KMnO4-> Include all steps of reaction, any additional reagents/conditions needed and the products formed. ive been stuck on this for hours need help please

chemistry
CH3CH2CHCHCH3 --HIO4-> | | HO OH Include all steps of reaction, any additional reagents/conditions needed and the products formed. ive been stuck on this for hours need help please

chemistry
CH3CH2CH=CHCH3 --KMnO4-> Include all steps of reaction, any additional reagents/conditions needed and the products formed. ive been stuck on this for hours need help please

Chem
Is this reaction endothermic or exothermic? Ca(C2H3O2)2(s) = Ca2+(aq) + 2C2H3O2-(aq)

Social Studies
Veterans day When did this first come about And who did do this What does this day mean to vets And what are some events that day

Chemistry
So is B correct, can someone explain

Math
Hi Bob - I have 4 possible answers and cannot arrive at any of them by the above. My choices are (a)634mph (b)1038mph (c)761mph (d)113mph

Math
The radius of Earth is 3,959 miles. A spacecraft orbits 6 miles above the surface of Earth. The spacecraft completes 220° of a revolution around Earth in one day. What is the average speed of the spacecraft?

physics
A 10.4 kg object oscillates at the end of a vertical spring that has a spring constant of 17500 N/m. The effect of air resistance is represented by the damping coefficient b = 3.00 N¡¤s/m.

Chemistry
A sample of hydrogen is collected over water at a total pressure of 648 mm Hg at 22 oC. The vapor pressure of water at 22 oC is 19.8 mm Hg. The partial pressure of the hydrogen is __________.

Social studies
Thank you Ms. Sue Anyone else have info to add to Ms. Sue's answer.

Social studies
Brief synopsis on the cause, effect and result Of the attack on Pearl Harbor. Six and one half Pages already typed and on cardboard made A flag, have pictures, just need alittle help In summarizing some facts you may have with The facts I have for the cardboard display Board. ...

Geometry
A museum was designed without windows, but a truncated cylindrical skylight lightens the building. In the development of this, the architect has areas where the angles formed at junctures are vertical angles. If a pair of vertical angles measures 5x - 54 and 3x -24, find the ...

Algebra
Tina's change of \$1.35 consisted of quarters and dimes only and she received twice as many dimes as quarters. How many dimes were there?

Algebra
At its grand opening, the gutherie market distributed two different types of souvenirs. One type costs 20 centseach, and the other type costs 25 cents each. One thousand souvenirs were distributed in all. If the cost of these souvenirs was \$220, how many of each type were ...

Algebra
The length of a rectangular playground exceeds twice its width by 25 meters, The perimeter of the playground is 650 meters. Find the demensions of the playground.

Chemistry
A sample weighing 3.064 g is a mixture of Fe2O3 (molar mass = 159.69) and Al2O3 (molar mass = 101.96). When heat and a stream of H2 gas is applied to the sample, the Fe2O3 reacts to form metallic Fe and H2O(g). The Al2O3 does not react. If the sample residue weighs 2.407 g, ...

Physics
A rocket of mass 1.0x10^3kg is being fired to a height of 5.0 x 10^3 m. The rocket engine shuts off when the rocket reaches a height of 1.0x10^3m, and the rocket coasts up to 5.0 x 10^3 m. A) What velocity must the rocket have at the 1.0x10^3 m point to enable it to reach 5.0 ...

Math
A local animal shelter had four more than six times as many adult cats as kittens. After eight of the kittens were adopted, the shelter had four fewer than eight times as many adult cats as kittens. How many adult cats are at the shelter?

chemistry
If a current of 5.0 Amps is passed through the electrolytic cell for .5 hour, how should you calculate the number of grams of bromine produced?

Chemistry
I took that answer (0.327 mmol) and divided it by 50ml to get my Molarity. But this does not seem correct. What am I doing wrong?

Chemistry
A 50.0 mL sample containing Cd2 and Mn2 was treated with 49.1 mL of 0.0700 M EDTA. Titration of the excess unreacted EDTA required 17.5 mL of 0.0300 M Ca2 . The Cd2 was displaced from EDTA by the addition of an excess of CN–. Titration of the newly freed EDTA required 10....

english
Point of View

College Chemistry
The specific Heat of gold is 0.128 J/g degrees Celsius. How much heat would be needed to warm 250.0g of gold from 25.0 degrees Celsius to 100.0 degrees Celsius

Social studies
What caused the Japanese ( what did the USA do) to attack Pearl Harbor.

Social studies
What caused the Japanese ( what did the USA do) to attack Pearl Harbor.

chemisty 2
Calculate the molarity (M) of a solution if you have 0.34 mol of NaOH in 19 ml of water

Math
2(2x+7)+(3x-5)=37

Math
2(2+7)+(6x-5)=37

Math
2(2+7)+(6x-5)=37

math
it has a picture with it but it wont past to the page

math
Write a number sentence for the model. Let one white tile equal +1 and one black tile equal –1. A. –14 – (–6) = –8 B. 14 – 6 = 8 C. –14 – 6 = –8 D. –14 – (–6) = 8 i put d but it was rong

Math
Radius of earth 3,959 miles Space shuttle orbits 200 miles above earths Surface Space shuttle completes 220 degrees of a Revolution around earth in one day What is the average speed of the space Shuttle

Math
Radius of earth 3,959 miles Space shuttle orbits 200 miles above earths Surface Space shuttle completes 220 degrees of a Revolution around earth in one day What is the average speed of the space Shuttle

Algebra
The cost of 5 similar cameras and 3 similar video cameras is \$3,213. Each video camera costs 4 times as much as each digital camera. John buys a digital camera and a video camera. How much does he pay?

CHEMISTRY
NH4OH + H2O =

physics
what is a satellite's altitude above the surface of the earth if earth's mass is 5.98*10^24 kg and its radius is 6380 km?

Chemistry
How many moles of KBr are present in 120mL of a 0.290M solution?

Chemistry
How many milliliters of 7.00M HCl solution are needed to obtain 0.200mol of HCl?

Physics
What does the tire preseeure reading in your vehicle signify? Is it an absolute pressure?

Chemistry
Calculate the concentrations of all species in a 1.41 M Na2SO3 (sodium sulfite) solution. The ionization constants for sulfurous acid are Ka1 = 1.4× 10–2 and Ka2 = 6.3× 10–8. Na^+ = 2.82M SO3^2- = 1.40M HSO3^- = 0.00047M H2SO3 = OH^- = H^+ = I have been ...

Chemistry
Calculate the concentrations of all species in a 1.41 M Na2SO3 (sodium sulfite) solution. The ionization constants for sulfurous acid are Ka1 = 1.4× 10–2 and Ka2 = 6.3× 10–8. Na^+ = 2.82M SO3^2- = 1.40M HSO3^- = 0.00047M H2SO3 = OH^- = H^+ = I have been ...

Physics
Two boys of the same mass, 45 kg, are on a playground merry-go-round that has a diameter of 4.0 meters. Both boys are at the very edge of the ride. One boy stands with the coefficient of friction between his shoes and eh ride being .45 whereas the other is on his knees with a ...

Elementary Math
-0.1<=y<=0.1 <= means less than or equal to So if I break the statement up is y <= -0.1 y>=0.1 Correct? Please help I'm confused.

Trigonometry
If a stake is placed in the ground and is 20cm. high and casts a shadow 12.5 cm. long, what time is it? (The sun rises at 6 a.m. and is overhead at noon.)

Math
Which statement illustrates the additive identity? a)3+0=3 b)3-3=0 c)3*0=0 d)3*1=3

Chemistry
Calculate the pH of 7.2 × 10-8 M HCl. Report your answer to the hundredths place. Next, What fraction of the total H in this solution is from the HCl? Report your answer to the hundredths place. I apologize for the re-post, but I felt the previous one was labeled ...

Analytical
I apologize, I saw my mistake, and used HCL (7.2E-8)/(Total) and got: 51.245% This answer is still wrong, so now I am thoroughly confused.

Analytical
Thank you very much for the reply. I was able to solve for X (X = 7.03E-8), which I added to that of HCl (Total = 1.405E-7) and was able to obtain the pH (6.85, assume this answer is deemed correct). Here is my problem: I took the (H^+) from HCL (X?) and divided it by the (...

Analytical
Calculate the pH of 7.2 × 10-8 M HCl. Report your answer to the hundredths place. Next, What fraction of the total H in this solution is from the HCl? Report your answer to the hundredths place.

algebra
Your salary after a 3% salary increase if your salary before the increase was S, what is the algebric expression?

Chemistry
How to do significant values in Chemistry? I am totally stuck; I have no idea what to do? My teacher gave me C due to the significant value error. Please help

math
Many thanks!!!

math
an urn contains 3 blue chips and 7 red chips. sequentially draw 3 chips without replacement. what is the probability that all drawn chips will not be the same color?

statistics
an urn contains 3 blue chips and 7 red chips. sequentially draw 3 chips without replacement. what is the probability that all drawn chips will not be the same color?

Algebra 1

Algebra 1
N/5-9=1/5

math
i mande 440 at a yard sell in 10 20 i need to have 5 more 10 than 20

algebra 2
y varies directly with x. When y = 20, x = 50. Find x when y = 36.

Math Stats
Chris is shopping for CDs and decides to purchase 3 movie soundtracks. The store has 9 different movie sountracks in stock. How many different selections of movie sountracks are possible?

math
1/3 + 5/6 = 7/6 7/6 + 3/8 = 37/24 37/24 = 1 13/24 or approx 1.5417

health
2. ________ in the pancreatic islets secrete the hormone insulin in response to a high concentration of glucose in the blood. A. Beta cells B. Alpha cells C. Gamma cells D. Sigma cells i put b but it said it was wrong

Physics
. The cheetah is the fastest running animal in the world. Cheetahs can accelerate to a speed of 20 m/s in 2.5 an can continue to accelerate to reach a stop speed of 29 m/s. Assume the acceleration is constant until the stop speed is reached and is zero thereafter. (a) Express ...

math
Ling bought 5 dishes and 9 glasses for \$25.50. Each glass cost 50¢ cents more than each dish. How much did Ling spend the glasses

trig
I think you mean find all angles theta between 0 and 2pi.

math
What is 77 percent round to nearest tenth of a degcree